Chris Eubank Jr's trainer Brian McIntyre has been charged with possession of a firearm and possession of ammunition for a firearm without a certificate.
Greater Manchester Police confirmed to Sky Sports News in a statement the 53-year-old had been charged following his arrest at Manchester Airport.
McIntyre attended Stockport Magistrates court on Monday morning and was remanded into custody, pending an appearance at Manchester Crown Court next month.
"At around 10.45am on Sunday, 3 September 2023, officers were called to reports of a possible firearm being found in hold luggage by airport staff at Manchester Airport," the statement from Greater Manchester Police read.
"After initial inspection by security staff, GMP officers attended, and the firearm was seized.
"Subsequently, a 53-year-old man was arrested for possession of a firearm and was taken to custody for further questioning.
"Brian McIntyre (01/07/1970) from the United States of America was charged with possession of a firearm and possession of ammunition for a firearm without a certificate.
"McIntyre attended Stockport Magistrates court this morning where he was further remanded into custody.
"He is next due to appear at Manchester Crown Court on Monday, 9 October 2023."
McIntyre was arrested after checking in ahead of his flight to Atalanta on Sunday morning.
The alarm was raised when UK Border Force intercepted baggage, after a scan allegedly showed a weapon, along with a magazine and ammunition contained within it.
Sky Sports News has been told armed police then descended upon the departure lounge at Manchester Airport's Terminal 2 to arrest McIntyre.
'BoMac' had been in the corner of Eubank Jr for his stoppage victory in his rematch against Liam Smith at Manchester Arena on Saturday night.
The trainer also works with undisputed welterweight world champion Terence Crawford.
Eubank Jr's team have told Sky Sports News they cannot comment at this stage.